Chair having a vertically adjustable seat



Feb. 20, 1951 R. A. CRAMER ET AL 2,542,480

CHAIR HAVING A VERTICALLY ADJUSTABLE SEAT Original Filed- March 16, 1944 IN VEN TORS Roy 'A.Cra17zr Rqy A.CJtulze ;Jr. Harold WCrancer attorneys Patented Feb. 20, 1951 UNITED STATES PATENT OFFICE CHAIR HAVING A VERTIOALLY ADJUST- ABLE SEAT Roy A. Cramer; Roy A. Cramer, Jr., and Harold W. Cramer, Kansas City, Mo.

4 Claims.

This invention relates to chairs and more particularly to improvements in. chairs. of the posture type which include a tiltable back rest which may automatically adjust itself to the back of the user.

Posture chairs of the type to which this invention appertains have heretofore been provided with various types of adjustments in order that the heights of the seat and back rest may be readily and quickly accommodated to the particular user of the chair. lfhis type of chair has been widely used in ofiices, factories and other places for seated workers, not only because of their ready adjustments but also because of their comfortable design in maintaining the body of the user in a posture-correct position.

For the most part, chairs of this type have heretofore been made of metal and close, precision machining methods have been employed. In constructing a chair of this character of wood, many problems are presented, one of the most serious of which is the problem of shrinking and swelling of the parts due to changes in temperature and moisture conditions. Shrinking causes looseness and wobble in the various parts, whereas swelling prevents the parts from moving freely with respect to each other. While the use of well-seasoned, selected hard woods tends to lesson these problems and diiliculties, still they are present in some degree, and wooden posture chairs heretofore provided have not been entirely satisfactory.

It is accordingly one of the ob ects of the present invent on to provide a posture chair which may be constructed of wood and which will avoid the above disadvantages.

Another object is to provide a chair which may be made entirely of metal and wherein the various parts are so constructed that precision machining thereof will be unnecessary.

Another object of the invention is to provide a novel chair construction wherein the parts are so constructed that they will efficiently cooperate with each other regardless of slight shrinking or swelling conditions due to changes in temperature and humidity.

Still another object is to provide a novel tiltable back rest for a chair of the above type, wherein the arrangement is such that the back rest may be automatically tilted in either direct'on, by the back of the user, to the most comfortable position.

Still another object is to provide arelatively simple but highly efiective support for the chair seat, the construction being such that wobble and lost motion are entirely eliminated.

A further object resides in the novel base: supporting structure whereby the chair spindle may be readily adjusted to vary the height of the seat and'wherein the seat. and spindle are sup ported in a substantial and rigid manner.

A still further object comprehends the provision of a novel and simplified chair structure which, while being of relatively low cost, is of sturdy and rigid construction and maintains proper cooperation of the parts thereof, regard less of their shrinking or swelling due to changes in. atmospheric conditions.

Other objects and novel features of the inven tion will appear more fully hereinafter from a consideration of the following detailed description when taken in connection with the accompanying drawing wherein one embodiment of the invention is illustrated. It isto be expressly un derstood, however, that the drawing is employed for purposes of illlustration only, and is not to be taken as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawing wherein similar reference characters refer to like parts throughout the several views: 7

Fig. 1 is a perspective view of the chair constructed in accordance with the present invention, certain parts being shown in section;

Fig. 2 is a transverse sectional view of the base construction taken along line 22 of 1 and looking in the direction of the arrows;

Fig. 3 is an axial sectional view of a portion of the base;

Fig. 4 is a partial sectional view illustrating the support for the back rest;

Fig. 5 is a fragmentary view partly in section of the seat support and spindle, and

Fig. 6 is a fragmentary view partly in section of the back rest supporting member.

Referring more particularly to Fig. 1, a chair constructed in accordance with the principles of the present invention is illustrated therein as comprising a seat Ill, a back rest H and a support 12. As shown, the support l2 has secured thereto, in any suitable manner, an upwardly extending tubular base l3 in which a seat-supporting spindle Hi is adapted to be adjustably positioned for varying the height of the seat it. The latter is secured to a spider l5 which coopcrates with the spindle M, in a manner which will appear more fully hereinafter, and which also adjustably receives, in any well known manher, see the patent to Roy A. Cramer No. 2,35 dated August 22, 1944, a horizontal member 16 which supports the back rest. The member I6 may be moved toward and away from the seat In in order to properly adjust the position of the back rest with respect to the seat, and may be locked. in its adjusted position by the thumb screw I'I.

One of the important features of the present invention resides in the novel arrangement for supporting the back rest. As shown, the member I6 receives a supporting post or arm I8, the upper end of which is provided with a recess I9 defined by side walls 28 and 2|, top wall 22, and bottom wall 23. An angle-shaped support preferably having integral arms 24 and 25 is pivotally mounted adjacent its hub to the side walls 28 and 2!, as by means of screws 26, the arm 24 extending outwardly beyond the edges of the said side walls and being connected with the back rest II. The arm 25 is so formed as to provide a pair of spaced apart leaf springs 2'! and 28 which extend downwardly and have their lower ends confined within a recess 29 in the bottom wall 23, see Fig. 4. With the described construction, the springs 21 and 28 normally serve to yieldingly maintain the back rest in the position illustrated in Figs. 1 and 4. However, the back rest may be yieldingly moved in either direction about its pivotal mounting, within the limits defined by the outer edges of the Walls 25), 2| and 22, the leaf springs always acting to urge the back rest to the normal position illustrated.

In order that the back rest may be readily adjusted to a suitable height with respect to the seat In, the arm I8 is adjustably mounted in member it. As shown, Figs. 1 and 6, the arm I8 is provided with a slot 38 with which the end of a clamping screw 3I, received by the member I6, cooperates, this construction providing for any height adjustment of the back rest, while preventing turning of the arm I8 relative to the member I6. Preferably the depth of the slot progressively increases from the top to the bottom thereof, so that if the clamping screw is not securely tightened, and the arm tends to drop downwardly, the bottom of the slot will tend to Wedge against the end of the clamping screw. It will be observed from Fig. 6 that the surface of the arm I8 adjacent the slot 30 is cut away or beveled at 32, from the upper end of the slot to the lower end thereof. This construction insures a maximum amount of engagement between the screw 3i and the member I8 regardless of the position of the arm I8.

Means are provided for removably mounting the seat-supporting spider E on the spindle I4 and preferably such means is so constituted that with the parts made of wood, no looseness or wobble will occur during any expansion or contraction of the parts. In the form shown, such means comprises a reduced end portion 33 having a lower beveled shoulder 34 and an upper beveled peripheral face or shoulder 35. The angularity of each of these beveled portions is preferably the same. The foregoing reduced end portion is adapted to be received within a socket 3B, of slightly greater diameter than the portion 33, the

said socket being provided with beveled shoulders ment effectively preventing the seat from being removed from the spindle, while permitting relative rotation between these two members.

It will be readily observed that with the foregoing construction, the seat is entirely supported upon the beveled shoulders 34 and 35, and that when the weight of the operator is upon the seat, a firm support is secured. This type of construction moreover maintains a firm support, without lost motion or binding, regardless of the expansion or contraction of the parts due to changes in atmospheric conditions. While the foregoing construction may be of wood, it is understood that any material, such as metal, may be used, and in the latter event, precision machining of the parts is avoided, while obtaining a firm and stable support.

The present invention, in addition to the foregoing, provides a novel arrangement for adjustably positioning and securing the spindle I4 in the base I3, and as shown, such arrangement is so constituted that the height adjustment of the spindle may be quickly eifected. For the above purposes, the base I3 is provided with a substantially cylindrical opening or bore 44 which extends downwardly from the top of the base and communicates with an enlarged opening 42. Adjacent the back of the bore M, the same is enlarged to form a portion 43, having a crescentshaped cross section, said portion extending the length of the bore 4|. With this arrangement a pair of bearing portions 44 and 45 are formed, as shown in Fig. 2, extending downwardly the full depth of bore M, for a purpose which will appear hereinafter.

Adjacent the front of the bore M, the base I3 is provided with a slot 46 for receiving an elongated locking member 41 having a head provided with a projection 48, adapted to be selectively engaged with one of the notches 49 on the spindle I4, and provided also with a supporting portion 50 cooperating with a ledge 5| on the base E3. The latter threadedly receives a clamping screw 52 which, when screwed inwardly, contacts the member 4'! substantially intermediate its ends and firmly forces said ends into engagement with the spindle and in turn forces the latter backwardly into engagement with the bearing portions 44 and 45. It will be noted that the looking member is so constructed that only the upper portion, in the form of projection 48, and the lower end, engage the spindle. With such a twopoint spaced-apart contact, it will be seen that as the screw 52 is screwed inwardly, a firm engagement will be insured between the spindle and portions 44 and 45 throughout the length of the latter. Thus, as will be observed from Fig. 2, the spindle I4 is firmly supported within the base at three places, spaced substantially equally around the circumference of the opening. Moreover, these three places constitute supporting surfaces which extend downwardly into the opening, a distance sufficient to achieve a firm and rigid support for the spindle when the screw 52 is tightened. The construction is especially advantageous when a wooden spindle and base are used, it being obvious that a tight and rigid support is secured regardless of sweling or shrinking.

It will be understood that when it is desired to adjust the height of the seat, the screw 52 is loosened and the locking member 4! is moved to the right, as viewed in Fig. 3, to withdraw projection 48 from notch 49. Thereafter, the spindle I4 is moved upwardly or downwardly to the desired position, the member 4'! is moved back to engage the proper notch 49, and the screw 52 is ghtened. The adjustment is thereby quickly and efiiciently effected.

In the event that the chair is used with the seat adjusted a substantial height above the floor, it may be desirable to provide an adjustable foot rest. Such an arrangement is illustrated in Figs. 1, 2 and 3 and comprises a platform 53, the rear portion of which is adapted to register with one of a plurality of notches 54. To the underside of the platform is secured a pair of arms 55 and 56, which bear against the base 13. When it is desired to vary the height of the platform, the same is tilted upwardly, as viewed in Fig. 1, to disengage the rear portion thereof from the notch 54. Thereafter, the platform is adjusted to the desired position, and moved downwardly to the position shown in Fig. 1.

This application is a division of our application Serial Number 526,734, filed March 16, 1944, for Chairs, now Patent No. 2,437,940 granted March 16, 1948.

The novel features heretofore described are particularly useful and advantageous in the event that the structural portions of the chair are made of wood, inasmuch as the arrangements are such that the various parts will cooperate in an eiiicient manner irrespective of shrinking or swelling due to changes in moisture conditions. However, it is to be understood that the chair may be made of metal parts if desired and in this connection it is pointed out that a substantial and rigid construction will result without the precision machining methods and closely fitting parts heretofore utilized.

While one embodiment of the invention has been illustrated herein, and described with considerable particularity, it is to be understood that the invention is not limited thereto but may be embodied in various other forms, without departing from the spirit or scope of the invention, as will appear to those skilled in the art. Reference will therefore be had to the appended claims for a definition of the limits of the invention.

We claim:

1. A chair comprising a base having an Opening therein, a seat-supporting spindle having a plurality of spaced notches along its length adapted to be received within said opening, and means for securing said spindle within the opening in the base comprising an elongated locking member within the opening having an upper part provided with a portion projecting laterally into one of said notches and another laterally projecting portion bearing upon the top of the base and having a lower part spaced a substantial distance from said upper part, and means threadedly positioned in the base intermediate the upper and lower parts of the locking member for, forcing the latter against the spindle and for securing the latter in said openmg.

2. A chair comprising an upwardly extending base having an opening therein for receiving a chair-supporting spindle, said spindle having spaced angularly related faces, said opening being formed to provide a pair of spaced angularly related bearing portions extending downwardly from the top of the base a substantial distance, a series of spaced-apart notches on said spindle, and means cooperating with said notches for securing the spindle in said opening to provide for different height adjustments of the spindle comprising a vertical locking member within the opening and having lateral portions cooperating with one of said notches, with the top of said base and a lower portion cooperating with said spindle, and means carried by the base for forcing said locking member against said spindle to force the latter into firm engagement with said bearing portions.

3. A chair comprising a cylindrical spindle provided with a plurality of notches spaced along the length of the spindle, an upwardly extending base having a substantially cylindrical opening for receiving and supporting said spindle, said opening being provided with a pair of spaced angularly related bearing portions extending downwardly from the top of the base, and means for securing said spindle in said opening at different height adjustments comprising an elongated locking member positioned within a downwardly extending slot open along one side into the opening in the base, said memher having an upper part provided with a lateral projection cooperating with one of said notches and a lateral portion contacting the top of the base, and having a lower part spaced from said upper part, and a screw carried by the base and cooperating with the locking member intermediate the upper and lower parts thereof for forcing the locking member into firm engagement with the spindle and for forcing the latter into engagement with said bearing portions.

4. A chair comprising a base having an opening therein, a seat-supporting spindle having a plurality of spaced notches along its length adapted to be received within said opening, and means for securing said spindle within the opening in the base comprising an elongated locking member within the opening having an upper part provided with a portion projecting laterally into one of said notches and another lateral portion bearing upon the top of the base and having a lower part spaced a substantial distance from said upper part and contacting the spindle, the locking member being so constructed and arranged that the part thereof intermediate the first portion and said lower part is out of contact with said spindle, and means threadedly positioned in the base intermediate the upper and lower parts of the locking member for forcing the latter against the spindle and for securing the latter in said opening.

ROY A. CRAMER. ROY A. CRAMER, JR. HAROLD W. CRAMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 300,116 Ocorr June 10, 1884 425,305 Daniels Apr. 8, 1890 498,703 Bobrick May 30, 1893 875,494 Bedell Dec. 31, 1907 1,731,461 Hansen Oct. 15, 1929 1,768,427 Stevens June 24, 1930 

